Piston construction



July 23, 1929.. V H. A. FLOGAUS PISTON CONSTRUCTION Filed. Aug. 31, 1928 mm H. 2 t

Patented July 23, 1929.

UNITED STATES 1,722,132 PATENT OFFICE.

HOWARD A. FLOGAUS, OF DETROIT, MICHIGAN, ASSIGNOR TO OF DETROIT, MICHIGAN.

RALPH L. SKINNER,

I PISTON CONSTRUCTION.

Application filed August 31, 1928. Serial No. 303,188.

With present-day, high-compression, internal-combustion engines it is important to permit the rapid escape or dissipation of the high degree of heat developed in the engine-cylinders, and it has been found to be desirable for this and other advantageous purposes, such as light weight of reciprocating parts, to employ pistons made of aluminum or aluminum alloys because. of their comparatively high coefficients of heat conduction.

Such pistons, however, expand much more readily and rapidly than do the cast-iron cylindersin which they reciprocate. and. accordingly, attempts have been made to reduce their expansion characteristics by mounting their skirts, at least in part, on metal bars of small heat expansion properties, but even this expedient does not overcome the undesired excessive or objectionable expansion qualities of the pistons.

If the pistons are fitted in their cylinders with sufficient clearance or looseness to allowv for the differences in heat expansion properties of the pistons and cylinders, then the pistons will slap in their cylinders, especially when the operation of the engine is first started, and, on the other hand, if the pistons are fitted sufliciently closely to avoid such objectionable noisy sla ping, the pistons, by reason of their quick initial enlargement, are likely to seize the cylinders and become unmovable therein with resulting serious damage to the engine, or, if the actual seizure does not occur, the pistons become detrimentally scufled or roughened. v,

The permissible tolerance between a tooclose fit and an adequately free piston-slap,

ping fitis so small as to be substantially impossible of attainment under ordinary manufacturing or mass production conditions.

' The result is that the engine manufacturers err on the safe side by making the piston clearances enough to avoid the pistons from becoming anchored or fixed in their cylinders by reason of their material differences in heat expansion.

In this connection, it may be borne in mind that, when the engine is first started, the heat I of the hot exploded gases is transmitted directly to the pistons and they enlarge comparatively rapidly, but the cylinders are surrounded by cooling-jackets', usually filled with water, and, accordingly, the cylinders cannot expand as readily by reason of the cooling eflect exerted on them by such enca'sing bodies of water, whose temperature must be raised in substantial measure before the cylinders can fully respond to the heat tending to expand them.

My invention relates to novel and improved cushioning means for the pistons to eliminate any disagreeable audible noises arising out of their rocking movements on their piston-pins into contact with the cylinder-walls.

Owing to the changes of angularity of the piston-rods, whose one end reciprocates and whose other end rotates, there is a decided tendency for their pistons to rock more or less noisily or audibly into hammering contact with the opposite Walls of their cylinders, and it is the main and leading purpose of this invent-ion to cushion such movements of the pisattached at its ends to the piston and to the associated connecting-rod at points highly favorable to the production of the required effects.

In the accompanying drawing such an embodiment of the invention has been illustrated in detail, and in its two.views, like reference numerals have been employed to designate the same structural parts.

In this drawing Figure ,1 is a central, longitudinal section on line 1-1 of Figure 2 through one cylinder of an internal-combustion engine in which the piston is supplied with the cushioning or dampening means; and V Figure 2 is a transverse or horizontal section on line 22 of Figure 1.

Referring to this drawing, the i nternalcombustion engine-cylinder has been denoted by the reference numeral 11 and the companion piston which reciprocates in it in the customary manner has been characterized 12, such piston having a head and a skirt, as is usual, and a plurality of piston-rings 13, 13.

The piston is rockingly mounted on a hollow pistonin 14, the ends of which oscillate in suita le bearings 15, 15 in the piston, the upper-split end of the associated connect-- ing-rod 16 being fixedly clamped on'the central portion of the piston-pin by means of a screw 17 all of which is the common way of connecting the specified elements together.

The skirt of thepiston, however, internally has a pair of registering bosses 18, 18, integraltherewith and apertured in alignmentto receive a hinge-pin rivet 19, the enlarged heads 21, 21 of which are accommodated in countersunk cavities 22, 22 extended inwardly from the outer surface of the piston.

Rockingly mounted on such rivet hingepin is the end loop or eye 23 of a i'nulti-lcaf, bowed or arched spring 24 extended aroundover the top of that upper portion of the connecting-rod encircling the piston-pin, the other or opposite end of the spring having a 1 like or similar eye or loop 25 similarly mounted on a hinge-pin 26 carried by spaced ears or lugs 27 27 of a suitably-shaped clip or bracket 28 apertured to receive the shank of the screw 17 and firmly and securely clamped between the head of the latter and the adjacent face of the connecting-rod head. I

In the present instance, the side of the piston is cut away at 29 to provide space for the movement of the adjacent end of the spring, although in many installations such mutilation of the piston is not necessary.

The spring is put into place, under compression, so that its two endsnormally tend to separate, and this capability is employed to cushion the rocking or turning movel'nents of the piston on the piston-pin, so that as the piston tends to swing on such pin into hammering engagement or contact with the piston wall, the force of such blow is sufiiciently absorbed or neutralized by the action of the spring that all objectionable or annoying noise or sound is quite overcome.

One problem to be solved in providing a construction of this character is to so design and arrange the cooperating elements that the spring can be of such size and length as to give it a degree or measure of resiliency which will assure its long life although undergoing repeated flexures with great rapidity.

I have found that a comparatively long spring of relatively great flexibility, as contrasted with a shorter spring of corresponding increased rigidity, not only will success- .fully withstand the required multiplicity of rapidly recurring fiexures or bending actions, but such a spring, in addition, permits of its attachment or mounting in place in such a'manner as to secure a greater leverage action on the piston.

The two characteristics or properties,

therefore, permit the use of a spring in the.

specified'relation which performs its function to the best advantage and the spring is capable of successfully withstanding or undergoing the quickly-occurring bending actions throughout a surprisingly long period. This result, in the present embodiment of the invention, is accomplished by securing the two ends of the spring to the piston and to the connecting-rod respectively on opposite sides of and at points well below the axis of the piston-pin, such arran ement enabling or allowing the use of a spring of such length that flexibility meets the requirements essential to long life and satisfactory operation, and the action of the spring on the piston is sufficiently below such axis as to insure a substantial leverage of the spring on the piston throughout. the range of rocking or oscillatory movement of the connecting-rod.

Although one embodiment only of the invention has been illustrated and described, it will be apparent to those skilled in this art that it is susceptible of various incorporations in physical form, all including or containing the fundamental principles of the invention. as defined by the appended claims.

It will be understood also that the shockabsorbing or cushioning spring in addition tends to remove or reduce any noises likely to otherwise occur by reason of undue looseness or play of the piston-pin in its bearings, and this will be true also in those constructions wherein the connecting-rod turns on the piston-pin. J

I claim: p

1.. The combination of a cylinder, a piston reciprocatory in said cylinder; a connectingrod adapted to be connected to a crank-shaft, a piston-pin rockinglv mounting said piston on said connecting-rod, said pistonat one side of and below the axis of said piston-pin having internal registering bosses integral therewith, ahinge-pin supported by said bosses, an arched leaf-spring extending over said piston-pin and rockingly mounted at one end on said hinge-pin, and means rockingly connecting the other'end of said spring to said connecting-rod on the opposite side of said piston-pin axis, said spring cushioning the swinging movements of said piston on said connecting-rod and thereby eliminating objectionable audible piston noises.

2. An internal-combustion engine piston having a pair of integral internal registering bosses on its skirt at one side of and below its piston-pin axis and adapted to support a se curing pin of a piston-cushioning spring.

'In witness whereof I have hereunto set my hand.

HOWARD A. FLOGAUS. 

